Lake Otero, X. Mcx. — Ucrrick. 175 
shadow the still greater, if more gradual, work of erosion 
which has planed awa}' the broken or arching strata, leaving 
the clear outlines of faulting more plainly in view ,than in 
any other region whatever. 
Any peak of the San Andres or S:icramento mountains in 
south-eastern New Mexico may become a veritable Pisgah to 
the trained observer, though it is history and not prophesy 
that will occupy him. The writer has briefly described the 
valley of the "white sands"* but in the present paper we 
are able to trace historical features not hitherto published. 
To one standing upon the foot-hills of the White or 
Sacramento mountains on the morning of a clear day and 
lookin.g west there is presented a view which cannot be dupli- 
cated elsewhere. At his feet is a nerirly level plain crossed 
from north to .south by the El Paso and North Eastern Rail- 
\\ay and dotted with a number of vill.'tges prominent among 
which is the new city of Alamogordo. each settlement being 
picked out by the bright green of the unfailing cotton woods. 
The vivid green of the grease- wood (Laria) fades as the 
plain is followed west. Numerous canons from the foot hills 
extend as arroyos all converging toward the central portion of 
the plain where they abruptly disappear. Still beyond, cov- 
ering an area of over 300 square miles, is a great white ex- 
panse of gypsum sands whose parallel dunes seem like frozen 
waves. It is impossible to escape the impression that one is 
looking out upon a great arm of the sea breaking in foam- 
like billows upon a low shore. Beyond, grey in the distance, 
are the outlines of the San Andres, whose irregular crests are 
capped with Carboniferous limestone d'pping west. 
A recent opportunity afforded by a survey of this area 
has permitted the writer to study this plain in considerable 
detail and not only to secure eviden':e of the truth of the 
theory of origin of the "'white sands" advanced in the pre- 
vious paper but also to work out the general outlines of the 
history of the entire basin. 
The origin of the great valley between the San Andres 
and Sacramento mountains is to be ittributed. as previously 
suggested, to a great anticline similar to that of the Rio 
Grande valley. This axis is nearly no'th and south but is not 
• Bull. Univ. \e\v \fex., vol. ii, Fasc. .T. 
